title: Comparison of causality analysis on simultaneously measured fMRI and NIRS signals during motor tasks.
abstract: Brain activity can be measured using different modalities. Since most of the modalities tend to complement each other, it seems promising to measure them simultaneously. In to be presented research, the data recorded from Functional Magnetic Resonance Imaging (fMRI) and Near Infrared Spectroscopy (NIRS), simultaneously, are subjected to causality analysis using time-resolved partial directed coherence (tPDC). Time-resolved partial directed coherence uses the principle of state space modelling to estimate Multivariate Autoregressive (MVAR) coefficients. This method is useful to visualize both frequency and time dynamics of causality between the time series. Afterwards, causality results from different modalities are compared by estimating the Spearman correlation. In to be presented study, we used directionality vectors to analyze correlation, rather than actual signal vectors. Results show that causality analysis of the fMRI correlates more closely to causality results of oxy-NIRS as compared to deoxy-NIRS in case of a finger sequencing task. However, in case of simple finger tapping, no clear difference between oxy-fMRI and deoxy-fMRI correlation is identified.
authors.forename: Abdul Rauf
authors.initials: AR
authors.lastname: Anwar
authors.forename: Makii
authors.initials: M
authors.lastname: Muthalib
authors.forename: Stephane
authors.initials: S
authors.lastname: Perrey
authors.forename: Andreas
authors.initials: A
authors.lastname: Galka
authors.forename: Oliver
authors.initials: O
authors.lastname: Granert
authors.forename: Stephan
authors.initials: S
authors.lastname: Wolff
authors.forename: Guenther
authors.initials: G
authors.lastname: Deuschl
authors.forename: Jan
authors.initials: J
authors.lastname: Raethjen
authors.forename: Ulrich
authors.initials: U
authors.lastname: Heute
authors.forename: Muthuraman
authors.initials: M
authors.lastname: Muthuraman
mesh_terms: D000328:Adult; D005260:Female; D005385:Fingers / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008962:Models, Theoretical; D009043:Motor Activity / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013647:Task Performance and Analysis; D013997:Time Factors